I have been using Ethernet to access the internet since i got the macbook a lil over a week ago, everything has been going fine, i used it this morning then took it out so i can move it more freely and watch a movie. Then when i tried to plug it back in, it just didnt recognize that it was connected, at first i thought it was the cord, so i plugged it into my other mac and it worked just fine, i even used a different cord on the macbook, Built-in Ethernet just didnt show up. Anyone have a similar problem ??? or know what it could be ?